To date, local area networks (LANs) basically have been used for connectionless transmission of data packets between computers. With the integration of the computer into communications services, not only data, but also voice and image information increasingly are transmitted via local area networks. The standard ITU-T H.323, for example, describes interfaces, necessary units and processes for packet-based multimedia communications systems.
FIG. 6 shows the basic structure of a device according to H.323. The terminals 61, 62 and 63, the gateway 64, the gatekeeper 66 and the multipoint control unit (MCU) 65 are connected to the packet-based network 60. The terminals 61–63 can communicate with one another via the network 60. To do this, however, they must register with the gatekeeper 66 and request transmission capacity (bandwidth) from it. The gateway 64 forms the interface between the device and other networks. The MCU 65 is defined in the H.323 standard for conference circuits.
In contrast to conventional terminals in communications systems, a computer, for example, can be disabled as a terminal and thereafter can no longer be contacted in the communications system. A call diversion is proposed in the standard H.450.3 which refines H.323, but the case of a terminal device which can be disabled is not taken into account. Therefore, if a terminal is disabled following activation of a call diversion, the call diversion is lost.
An object of the present invention is, therefore, to provide a method and a device which guarantee a call diversion, even for terminals which can be disabled in a communications system.